1. Field of the Invention
The present invention relates to a rearview mirror for various vehicles, particularly for an automobile vehicle.
2. Description of the Prior Art
The rearview mirror of the type described in French Pat. No. 2,569,638 includes a mirror-holder casing extended by a fork joint between the arms of which extends a cylindrical appendix of a fixed base adapted to be mounted on the vehicle. A fixed jaw presenting two friction bearing surfaces, one plane and the other cylindrical, respectively, is interposed between the fixed appendix and one of the arms of the fork joint to be manoeuvred. A mobile jaw presenting two friction bearing surfaces, one plane and the other cylindrical, respectively, is interposed between the fixed appendix and a mobile piece borne by the other arm of the fork joint. A forward-rearward pivot pin passes through the arms of the fork joint, the jaws, the appendix and the mobile piece. A single spring abutting on a stop of the pin pushes the mobile piece, which is guided in the fork joint in the direction of the pin to press all the friction bearing surfaces against one another. Finally, an indexing device is interposed between the mirror-holder casing and the appendix of the fixed base in order that, in the event of a shock, the rearview mirror can retract forwardly or rearwardly by elastic deformation of a member of the indexing device.
In this known rearview mirror, it is relatively difficult to adjust with respect to one another the efforts of manoeuvring for the forward-rearward pivoting about the axis by friction of the plane bearing surfaces and for upward-downward pivoting about the appendix by friction of the cylindrical bearing surfaces. In fact, for the dimensions of the internal pivoting mechanism to remain within admissible limits, the cooperating pieces must be adapted to one another by acting on the nature of the materials of which they are constituted. The search for maximum reliability and minimum cost is not compatible with this. In addition, it is nonetheless impossible to obtain a fine adjustment of the ratio between these efforts.
Attempts to incorporate springs within the known device have been made for specific purpose. For example French Pat. No. 2,311,689 discloses a rearview mirror having a base and a casing in which a mirror is adjustable in forward-rearward position and in upward-downward position. A double articulation connecting the casing to the base and through which extends the control of the mirror is disclosed therein. The articulation is designed toa llow retraction of the casing in the event of a shock and its indexing in neutral position. It has two vertical-axis cylindrical bosses opposing their convexity and applied against an intermediate hollow spacer piece, the assembly being traversed by a tubular bush provided for the passage of the control mentioned above. A first spring is interposed between a shoulder of the bush and the first boss of the base; a second spring is interposed between a nut of the bush and the second boss of the casing.
The springs, therefore, do not allow adjustment of the mirror, but retraction of th casing under the effect of a shock, the ribs on the bosses and the grooves in the spacer piece ensuring indexing.
German Pat. No. 1,266,653 discloses a rearview mirror having abase on which is mounted a casing containing a fixed mirror. As shown in FIG. 2, the function of forward-rearward and upward-downward adjustment is ensured by a ball joint of the casing applied against a likewise spherical bearing surface of the base by a single spring. For retraction in the event of a shock, a rod extending the ball joint traverses an elongated slot in the casing and may slide therein. Indexing is ensured by the penetration, under the action of another spring, of a boss of the ball joint in a recess in the casing.
The first spring allows adjustment of the mirror in all directions, while the second spring allows only retraction in the event of shock and indexing. Accordingly, what is needed is a reliable, cost effective adjustment feature providing for the fine adjustment of the ratio between the aforementioned efforts.